Faunt, Claudia C.2012Contours of Corcoran Clay Thickness in feet by Page (1986) for the Central Valley Hydrologic Model (CVHM)vector digital dataProfessional Paper1766Reston, VirginiaU.S. Geological Surveyhttp://water.usgs.gov/lookup/getspatial?pp1766_corcoran_clay_thickness_feetFaunt, C.C.2009Groundwater Availability of the Central Valley Aquifer, CaliforniaProfessional Paper1766Reston, VirginiaU.S. Geological Surveyhttp://pubs.usgs.gov/pp/1766/PP_1766.pdfThis digital dataset defines the thickness of the Corcoran Clay Member of the Tulare Formation. The complex hydrologic system of the Central Valley is simulated using the USGS numerical modeling code MODFLOW-FMP (Schmid and others, 2006b). This simulation is referred to here as the Central Valley Hydrologic Model (CVHM) (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. Numerous lenses of fine-grained sediments are distributed throughout the southern Central Valley (San Joaquin Valley) and generally constitute more than 50 percent of the total thickness of the valley fill. Generally, these lenses are discontinuous and not vertically extensive or laterally continuous. However, the Corcoran Clay is a low-permeability, areally extensive, lacustrine deposit (Johnson and others, 1968) as much as 200 feet thick (Davis and others, 1959; Page, 1986). This continuous clay divides the groundwater-flow system of the western San Joaquin Valley into an upper semi-confined zone and a lower confined zone (Williamson and others, 1989; Belitz and Heimes, 1990; Burow and others, 2004). The extent and distribution of the Corcoran Clay was defined for use in the CVHM because the unit is one of the few deposits in the Valley that can be regionally mapped. The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS). The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details).The thickness of the Corcoran Clay Member of the Tulare Formation is used to help define the 3-dimensional extent of the Corcoran Clay for the CVHM. In the CVHM flow simulation, the Corcoran Clay is generally a fine-grained confining layer and is simulated separately by layers 4 and 5. The CVHM is a tool that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system.The thickness of the Corcoran Clay dataset is one of many layers in a geospatial database supporting the USGS Central Valley Groundwater Availability Project. Regional groundwater availability studies quantify current groundwater resources, evaluate how those resources have changed through time, and provide tools that decision makers can use to predict system responses to future development and climate variability and change. To provide information to stakeholders addressing these issues, the USGS made a detailed assessment of groundwater availability of the Central Valley aquifer system, which includes: (1) the present status of groundwater resources; (2) characterization of how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at various scales. Data from these previous studies were the foundation of the Central Valley geospatial database. These and other data were re-examined through a series of regional-scale hydrologic investigations to provide updated and spatially consistent interpretations for the Central Valley Groundwater Availability study. In some cases, new data were collected to augment existing information. Data compiled from the studies include geology (in particular, borehole lithology and the extent and thickness of the Corcoran Clay Member of the Tulare Formation), topography, remote sensing, climate (precipitation and temperature), geophysics, vegetation and land use, vegetation properties, hydrology (stream network and flows), groundwater levels, subsidence, chemistry, and soils. Digital elevation models, geologic maps, borehole information, cross sections, and other 3-dimensional models were used to develop the texture model which represents the properties and geometry of the Central Valley alluvial deposits. The resulting geospatial database supports characterization and conceptualization of the Central Valley hydrologic system between 1961 and 2003, construction of 3-dimensional hydrogeologic framework and hydrologic flow models, and visualization of analysis and model results.2009publication dateCompleteNone planned-121.520515-118.78735937.81487435.009307ISO 19115 Topic CategorygeoscientificinformationAmerican Geological Institute Glossary of Geology. (http://glossary.agiweb.org/dbtw-wpd/glossary/search.aspx)hydrologyhydrogeologygroundwatermodelnoneCentral Valley AquiferGroundwater Availability of the Central Valley AquiferCentral Valley Hydrologic ModelCV-RASAFlow Model CVHMTexture ModelCorcoran ClayU.S. Board of Geographic Names (BGN) and Geographic Names Information System (GNIS)CaliforniaCentral ValleySan Joaquin CountyStanislaus CountyMerced CountyMadera CountyFresno CountyTulare CountyKings CountyKern CountyNone.
Data have been checked to ensure the accuracy of the data. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein.
Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology.
Claudia C. FauntU.S. Geological SurveyHydrologistmailing and physical addressCalifornia Water Science CenterSan DiegoCalifornia92101USA(619) 225-6142(619) 225-6101ccfaunt@usgs.govhttp://water.usgs.gov/GIS/browse/pp1766_corcoran_clay_thickness.pngIlllustration of data setpngSpatial datasets supporting the Central Valley Groundwater Availability project were developed primarily by the U.S. Geological Survey's (USGS) Groundwater Resources Program. This program is conducting large-scale multidisciplinary regional studies of groundwater availability. The U.S. Bureau of Reclamation is supporting the updating of the Central Valley datasets and their documentation and release.Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3500Page, R. W.1986Geology of the Fresh Ground-Water Basin of the Central Valley, California, with Texture Maps and SectionsProfessional Paper1401-CReston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/pp/1401c/report.pdfSchmid, WolfgangHanson, R. T.Maddock, Thomas, IIILeake, S. A.2006bUser guide for the farm process (FMP1) for the U.S. Geological Survey's modular three-dimensional finite-difference ground-water flow model, MODFLOW-2000Techniques and Methods6-A17Sacramento, CAUSGS California Water Science Centerhttp://pubs.usgs.gov/tm/2006/tm6A17/Burow, Karen R.Shelton, Jennifer L.Hevesi, Joseph A.Weissmann, Gary S.2004Hydrogeologic characterization of the Modesto Area, San Joaquin Valley, CaliforniaScientific Investigations Report2004-5232Reston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/sir/2004/5232/Johnson, A. I.Moston, R. P.Morris, D. A.1968Physical and hydrologic properties of water-bearing deposits in subsiding areas in central CaliforniaProfessional Paper497-AReston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/pp/0497a/report.pdfDavis, G. H.Green, J. H.Olmsted F. H.Brown, D. W.1959Ground-water conditions and storage capacity in the San Joaquin Valley, CaliforniaWater Supply Paper1469Washington, D.C.US Government Printing Officehttp://pubs.usgs.gov/wsp/1469/report.pdfWilliamson, A. K.Prudic, D. E.Swain, L. A.1989Ground-water flow in the Central Valley, CaliforniaProfessional Paper1401-DReston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/pp/1401d/report.pdfBelitz, Kenneth R.Heimes, Frederick J.1990Character and evolution of the ground-water flow system in the central part of the western San Joaquin Valley, CaliforniaWater Supply Paper2348Reston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/wsp/2348/report.pdfAttributes added by the GIS and the data-set author were checked by inspection using a GIS. In addition, attributes were checked and evaluated as part of the review process associated with the publication of the source report.Lines forming polygons join at endpoints to completely enclose defined areas. Lines not enclosing areas do not intersect. No duplicate line features exist and all nodes are represented by a single coordinate pair which indicates the beginning or end of a line. All vertices that define the shape of the line are represented by a unique coordinate pair.The line features in this dataset are computer-generated and represent the Corcorcan Clay thickness layers in the Central Valley Hydrologic Model. The dataset is complete and is not anticipated to change.Horizontal positional accuracy of line features in the dataset was tested by visually comparing to digital source maps by using a GIS system.Faunt, C. C.Hanson, R.T.Belitz, K.2009Chapter A - Introduction, Overview of Hydrogeology, and Textural Model of California's Central ValleydocumentU.S. Geological Survey Professional Paper2009-1766Reston, VirginiaU.S. Geological Surveyhttp://pubs.usgs.gov/pp/1766/PP_1766.pdfFaunt, C.C.2009Groundwater Availability of the Central Valley Aquifer, CaliforniaU.S. Geological Survey Professional Paper2009-1766Reston, VirginiaU.S. Geological Survey500000online20091986Faunt and others (2009)See Professional Paper 1766 - Groundwater Availability of the Central Valley Aquifer, California.Page, R. W.1986Geology of the fresh ground-water basin of the Central Valley, California, with texture maps and sectionsProfessional Paper1401-CReston, VAU.S. Geological Surveyhttp://pubs.usgs.gov/pp/1401c/report.pdfonline2009publication datePage and Others, 1986Linework and Contour ValuesThe 1:500,000 scale plate of the contour lines was scanned into a 300 dots per inch .tiff image A GIS was used to georeference and trace/digitize the contour lines by hand into a shapefile. Each contour-line attribute was populated with the thickness (in feet) of the Corcoran Clay.Page (1986)0401200508303600Faunt, C.C.USGSHydrologistmailing and physical address4165 Spruance Road, Suite 200San DiegoCA92101USA(619) 225-6142ccfaunt@usgs.govCentral Valley, comprised of the Sacramento Valley on the north and the San Joaquin Valley on the south, located in the state of California.VectorString317Albers Conical Equal Area29.50000045.500000-120.00000023.0000000.0000000.000000coordinate pair100100metersNorth American Datum of 1983Geodetic Reference System 806378137.000000298.257222corcoran_clay_thickness_feetThickness of Corcoran Clay in Feetdataset originatorFIDInternal feature number.ESRISequential unique whole numbers that are automatically generated.ShapeFeature geometry.ESRICoordinates defining the features.THICKNESSThickness of Corcoran Clay layer in feetPage (1986)10200Feet10There are 317 records in this shapefile. It has two attributes that are generated by the GIS (FID and Shape) for internal software purposes. The remaining attribute was assigned by the author (dataset Originator) to define and describe the thickness of the Corcoran Clay layer in feet. These data were used for analysis and for developing input files for the CVHM textural model and numerical ground-water flow model.None.U.S. Geological SurveyAsk USGS -- Water Webserver Teammailing address445 National CenterRestonVA20192USA1-888-275-8747 (1-888-ASK-USGS)http://water.usgs.gov/user_feedback_form.html
Downloadable Data
Digital geospatial datasets for the textural model and numerical model of the hydrogeologic landscape and groundwater flow in California's Central Valley.
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials.
The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners.SHPESRI Shapefile0.0450439453http://water.usgs.gov/GIS/dsdl/pp1766_CorcoranClay.zipNone. This dataset is provided by the USGS as a public service.201120120824U.S. Geological SurveyAsk USGS -- Water Webserver Teammailing address445 National CenterRestonVA20192USA1-888-275-8747 (1-888-ASK-USGS)http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Datase+pp1766_corcoran_clay_thickness_feetFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998